TWI737178B - Methods for reducing sticking of an object to a modified surface, support structures, and related non-transitory machine-readable medium - Google Patents

Abstract

Methods, computer program products, and apparatuses for reducing sticking during a lithography process are disclosed. An exemplary method of reducing sticking of an object to a modified surface that is used to support the object in a lithography process can include controlling a light source to deliver light to a native surface thereby causing ablation of at least a portion of the native surface to increase the roughness of the native surface thereby forming the modified surface. The increased roughness reduces the ability of the object to stick to the modified surface.

Description

Method, support structure, and related non-transitory machine-readable media for reducing the adhesion of objects to modified surfaces

This application is about laser roughening, and specifically about the roughness of the top of the engineered nodule.

The lithographic projection device can be used, for example, in the manufacture of integrated circuits (IC). In this case, the patterned device (such as a mask) can contain or provide a pattern corresponding to the individual layer of the IC ("design layout"), and this pattern can be used to irradiate the target, such as through the pattern on the patterned device Part of the method is transferred to a target part (for example, containing one or more dies) on a substrate (for example, a silicon wafer), which has been coated with a layer of radiation-sensitive material ("resist"). Generally speaking, a single substrate contains a plurality of adjacent target portions, and the pattern is sequentially transferred to the plurality of adjacent target portions by the lithographic projection device, one target portion at a time. In one type of lithographic projection device, the pattern on the entire patterned device is transferred to a target part at a time; this device can also be called a stepper. In an alternative device, the step-and-scan device can make the projection beam scan across the patterned device in a given reference direction ("scanning" direction), while simultaneously moving the substrate parallel or anti-parallel to this reference direction. Different parts of the pattern on the patterned device are gradually transferred to a target part. Generally speaking, since the lithography projection device will have a reduction ratio M (for example 4), the speed F of the moving substrate will be the speed of the projection beam scanning the patterned device 1/M times. More information about lithographic devices can be found in, for example, US 6,046,792, which is incorporated herein by reference.

Before transferring the pattern from the patterned device to the substrate, the substrate may undergo various processes, such as priming, resist coating, and soft baking. After exposure, the substrate can undergo other processes ("post-exposure process"), such as post-exposure bake (PEB), development, hard bake, and measurement/inspection of the transferred pattern. This process array is used as the basis for making individual layers of a device (such as an IC). The substrate can then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, chemical mechanical polishing, etc., all of which are intended to finish individual layers of the device. If several layers are required in the device, the entire process or its variants are repeated for each layer. Eventually, there will be devices in each target portion on the substrate. These devices are then separated from each other by techniques such as cutting or sawing, whereby individual devices can be mounted on the carrier, connected to pins, etc.

Therefore, manufacturing a device such as a semiconductor device usually involves using several manufacturing processes to process a substrate (eg, a semiconductor wafer) to form various features and multiple layers of the device. Such layers and features are usually manufactured and processed using, for example, deposition, lithography, etching, chemical mechanical polishing, and ion implantation. Multiple devices can be fabricated on multiple dies on a substrate, and then these devices can be separated into individual devices. This device manufacturing process can be regarded as a patterning process. The patterning process involves a patterning step, such as optical and/or nanoimprint lithography that uses the patterning device in the lithography device to transfer the pattern on the patterned device to the substrate, and the patterning process is usually but may involve One or more related pattern processing steps, such as resist development by a developing device, baking a substrate with a baking tool, etching with a pattern using an etching device, and the like.

As mentioned, lithography is a central step in the manufacture of devices such as ICs, in which the patterns formed on the substrate define the functional elements of the device, such as microprocessors, memory chips, and the like. Similar lithography technology is also used to form flat panel displays, microelectromechanical systems (MEMS) and other devices Pieces.

As the semiconductor manufacturing process continues to advance, the size of functional elements has been continuously reduced for decades, and the amount of functional elements such as transistors in each device has been steadily increasing. This follows the so-called "Moore's Law ( Moore's law)” trend. In the current state of the art, lithographic projection devices are used to fabricate the layers of the devices. These lithographic projection devices use illumination from a deep ultraviolet illumination source to project the design layout onto the substrate, resulting in a size far below 100nm (ie, Individual functional elements that are less than half the wavelength of the radiation from the illumination source (for example, a 193nm illumination source).

This process for printing features smaller than the classic resolution limit of the lithographic projection device can be called low-k1 lithography according to the resolution formula CD=k1×λ/NA, where λ is the wavelength of the radiation used (for example, 248nm or 193nm), NA is the numerical aperture of the projection optics in the lithographic projection device, CD is the "critical size" (usually the smallest feature size printed), and k1 is the empirical resolution factor. Generally speaking, the smaller k1 is, the more difficult it is to regenerate a pattern similar to the shape and size planned by the designer in order to achieve specific electrical functionality and performance on the substrate. In order to overcome these difficulties, complex fine-tuning steps are applied to lithographic projection devices, design layouts, or patterned devices. These steps include, for example, but not limited to, optimization of NA and optical coherence settings, customized lighting schemes, use of phase shift patterning devices, optical proximity correction (OPC, sometimes referred to as "optical and Process Calibration”), or other methods generally defined as “Resolution Enhancement Technology” (RET). The term "projection optics" as used herein should be broadly interpreted as covering various types of optical systems, including, for example, refractive optics, reflective optics, apertures, and catadioptric optics. The term "projection optics" may also include components that operate according to any of these design types to collectively or individually direct, shape, or control the projection radiation beam. The term "projection optics" can include any of the lithographic projection devices Optical components, regardless of where the optical components are located on the optical path of the lithographic projection device. The projection optics may include optical components for shaping, conditioning, and/or projecting radiation from the source before it passes through the patterned device, and/or for shaping, conditioning, and/or after the radiation passes through the patterned device Or the optical component that projects the radiation. Projection optics usually do not include source and patterning devices.

A method for reducing the adhesion of an object to a modified surface used to support the object in a lithography process is disclosed. The method includes controlling a light source to deliver light to a native surface, thereby causing the ablation of at least a portion of the native surface to increase the roughness of the native surface, thereby forming the modified surface. The increased roughness reduces the ability of the object to adhere to the modified surface.

In some variations, the light source may be a laser, and the native surface may include a top surface of a nodule. The control of the light source may include setting an energy density of the light source to generate light with a flux at the primary surface, which when delivered to the surface results in the primary surface based on an atomic structure of the primary surface Selective ablation, the selective ablation reduces a surface area used to contact the object. The primary surface may have crystal grains separated by grain boundaries, wherein the selective ablation removes the material of the grain boundaries and does not substantially result in the removal of the crystal grains. In addition, the control may include adjusting one or more of an intensity and/or focus of the light source to set the energy density based on a desired roughness of the modified surface.

In other variations, the control may include delivering light at a separation site on the native surface that causes ablation of a portion of the grain boundaries, the delivery causing the modified surface to include roughened areas with a distance therebetween. The separation distance can be greater than the size of a spot of the light source. In addition, a distance between the light delivery locations can be smaller than the size of a light spot of the light source. The light delivery also It can straddle hilltops, which are located on the top surface of a nodule that forms part of a reticle clamp.

In a related aspect, a non-transitory machine-readable medium stores instructions that, when executed by at least one programmable processor, cause the programmable processor to perform operations, the operations including controlling a light source to Light is delivered to a native surface, whereby the excision of at least a portion of the native surface increases the roughness of the native surface, thereby forming a modified surface, wherein the increased roughness reduces the adhesion of an object to the modified surface Sexual surface ability.

In some variations, the control may include setting an energy density of the light source to generate light with a flux at the primary surface, which when delivered to the surface is based on an atomic structure of the primary surface. Selective ablation of the native surface, the selective ablation reduces a surface area used to contact the object.

In addition, in other variations, the control may include adjusting one or more of the intensity and/or focus of the light source to set the energy density based on a desired roughness of the modified surface. The control may further include delivering light at a separation site on the native surface that causes ablation of a portion of the grain boundaries, the delivery causing the modified surface to include roughened areas with a distance therebetween.

In yet another related aspect, a device may have a modified surface configured to contact an object, the modified surface being formed of a material including a crystal grain structure, the crystal grain structure including crystal grains And grain boundaries, wherein the modified surface has a roughness based at least on crystal grain peaks and crystal grain boundary valleys located below the crystal grain peaks.

In some variations, the roughness may be the root mean square of the height of the modified surface. The roughness can be between 3nm and 35nm, between 20nm and 35nm, or greater than 2nm. In addition, the roughness of the primary surface may be less than 3 nm. The device can be used in the modified table In at least one part of the surface, the grain boundary material between 2 nm and 30 nm is removed from the primary surface.

In other variations, the device may include nodules extending from a substrate, wherein the modified surface is located on the top surface of the nodules. The substrate can be a double-reduction mask fixture, a wafer fixture or a wafer table. The device may include a coating on the top surfaces of the nodules, and the modified surface is formed in the coating. The coating can be TiN, CrN or DLC coating. The nodules may include a plurality of hillocks, and the modified surface is located on the plurality of hillocks, and the modified surface may include a roughened area formed across the hillocks.

In other variations, the modified surface may include roughened areas with a distance therebetween. The distance between the roughened areas may be about 10 microns, about 15 microns, or about 20 microns. The modified surface may have an arithmetic average height (Sa) between 0.4 nm and 19 nm. The modified surface includes roughened areas where approximately 5 nm of material in at least one of the grain boundaries has been removed.

10A: Lithography projection device

12A: Radiation source

14A: Optics

16Aa: Optics

16Ab: Optics

16Ac: Transmission optics

18A: Patterned device

20A: Aperture

22A: substrate plane

31: Source model

32: Projection optics model

35: design layout model

36: Aerial Image

37: resist model

38: resist image

310: Wafer

320: Wafer table

330: Tumor

340: Tumor Surface

410: substrate

420: Coating

430: Tumor Surface

510: Crystal Grain

520: Crystal Boundary

530: Native Surface

610: Native Surface

612: lens

620: light

630: focus

710: modified surface

720: Crystalline grain peak

730: Crystalline Grain Boundary Valley

810: Separation part

820: distance

830: small hill

AD: adjust the device

B: Radiation beam

BS: Bus

C: target part

CC: cursor control/collector chamber

CI: Communication interface

CO: Concentrator/Radiation Collector

CS: Computer System

CT: pollutant trap

DS: Display/downstream radiation collector side

ES: enclosure structure

Ex: beam expander

FM: Faceted field mirror device

GR: Grazing incidence reflector

HC: main computer

HP: Thermoplasma

ID: input device

IF: Interference measuring device/virtual source point

IL: lighting system/lighting optics unit

IN: Accumulator

INT: Internet

LA: Laser

LAN: Local Area Network

LPA: Lithography projection device

M1: Patterned device alignment mark

M2: Patterned device alignment mark

MA: Patterned device

MM: main memory

MT: The first object platform

NDL: network link

O: Optical axis/dotted line

OP: opening

P1: substrate alignment mark

P2: substrate alignment mark

PB: beam

PL: lens

PM: the first locator

PRO: processor

PS: Projection system/project

PS1: Position sensor

PS2: Position sensor

PW: second locator

RE: reflective element

ROM: Read only memory

SC: source chamber

SD: storage device

SF: grating spectral filter

SO: Radiation source/source collector module

US: Upstream radiation collector side

W: substrate

WT: The second object platform

X: direction

Y: direction

The accompanying drawings incorporated into and forming a part of this specification show some aspects of the subject matter disclosed herein, and together with the description help clarify some principles associated with the disclosed implementation. In this diagram,

FIG. 1 is a block diagram of various subsystems of a lithography projection apparatus according to an embodiment.

2 is an exemplary flowchart for simulating lithography in a lithography projection device according to an embodiment.

FIG. 3 is a simplified top view of a wafer placed on a nodule surface of a wafer table according to an embodiment.

Figure 4 is a simplified side view of an exemplary nodule with a coating according to an embodiment.

5 is a schematic diagram of a side cross-sectional view of an exemplary nodule having crystal grains and crystal grain boundaries according to an embodiment.

6 is a schematic diagram of an exemplary cross-sectional view of a nodule receiving light at a primary surface formed by a crystal grain and a crystal grain boundary according to an embodiment.

Fig. 7 is a schematic view of the nodule of Fig. 6 according to an embodiment, the nodule being roughened to form a modified surface by cutting a part of the crystal grain boundary.

FIG. 8 is a schematic diagram illustrating an exemplary nodule with a small hillock top formed on a separated roughened area on the nodule according to an embodiment.

FIG. 9 is a diagram illustrating a roughness map according to an embodiment.

Fig. 10 is a process flow chart for controlling a tool to form grooves and ridges according to an embodiment.

FIG. 11 is a block diagram of an example computer system according to an embodiment.

Fig. 12 is a schematic diagram of a lithography projection apparatus according to an embodiment.

FIG. 13 is a schematic diagram of another lithography projection apparatus according to an embodiment.

Fig. 14 is a detailed view of the lithography projection apparatus according to an embodiment.

FIG. 15 is a detailed view of the source collector module of the lithographic projection device according to the embodiment.

Although specific reference can be made to the manufacture of ICs in this article, it should be clearly understood that the description in this article has many other possible applications. For example, it can be used for integrated optics Manufacturing of systems, guiding and detecting patterns of magnetic domain memory, liquid crystal display panels, thin-film magnetic heads, etc. Those familiar with this technology should understand that in the context of such alternative applications, any use of the terms "reduced mask", "wafer" or "die" in this article should be regarded as separate and more general The terms "mask", "substrate" and "target part" are interchanged.

In the literature of the present invention, the terms "radiation" and "beam" are used to cover all types of electromagnetic radiation, including ultraviolet radiation (for example, having a wavelength of 365nm, 248nm, 193nm, 157nm or 126nm) and extreme ultraviolet radiation (EUV, For example, it has a wavelength in the range of about 5nm to 100nm).

The patterned device may include or may form one or more design layouts. Computer-aided design (CAD) programs can be used to generate design layouts. This process is often referred to as electronic design automation (EDA). Most CAD programs follow a predetermined set of design rules in order to produce functional design layout/patterned devices. Set these rules by processing and design constraints. For example, design rules define the space tolerance between devices (such as gates, capacitors, etc.) or interconnect lines to ensure that the devices or lines do not interact with each other in an undesired manner. One or more of the design rule constraints can be referred to as "critical dimensions" (CD). The critical dimension of the device can be defined as the minimum width of a line or hole or the minimum space between two lines or two holes. Therefore, CD determines the overall size and density of the designed device. Of course, one of the goals of device manufacturing is to faithfully reproduce the original design intent on the substrate (via patterned devices).

The term "mask" or "patterned device" as used herein can be broadly interpreted as referring to a general patterned device that can be used to impart a patterned cross-section to an incident radiation beam, the patterned cross-section corresponding to The pattern to be generated in the target portion of the substrate; the term "light valve" can also be used in the context of this content. In addition to classic masks (transmissive or reflective; binary, phase shift, hybrid, etc.), other examples of such patterned devices include programmable mirror arrays Rows and programmable LCD array.

An example of a programmable mirror array can be a matrix addressable surface with a viscoelastic control layer and a reflective surface. The basic principle underlying this device is (for example): the addressed area of the reflective surface reflects incident radiation as diffracted radiation, while the unaddressed area reflects incident radiation as non-diffracted radiation. With appropriate filters, the non-diffracted radiation can be filtered out from the reflected beam, leaving only diffracted radiation; in this way, the beam becomes patterned according to the addressing pattern of the matrix addressable surface. Appropriate electronic methods can be used to perform the required matrix addressing.

Examples of programmable LCD arrays are given in US Patent No. 5,229,872, which is incorporated herein by reference.

FIG. 1 illustrates a block diagram of various subsystems of a lithographic projection apparatus 10A according to an embodiment. The main components are: radiation source 12A, which can be a deep ultraviolet excimer laser source or other types of sources including extreme ultraviolet (EUV) sources (as discussed above, the lithographic projection device itself does not need to have a radiation source); illumination optics Devices, which, for example, define partial coherence (expressed as mean square deviation) and may include optics 14A, 16Aa, and 16Ab that shape the radiation from source 12A; patterned device 18A; and transmissive optics 16Ac, which will pattern The image of the device pattern is projected onto the substrate plane 22A. The adjustable filter or aperture 20A at the pupil plane of the projection optics can limit the range of beam angles irradiated on the substrate plane 22A, where the largest possible angle defines the numerical aperture of the projection optics NA=n sin(Θ _max ), where n is the refractive index of the medium between the substrate and the final element of the projection optics, and Θ _max is the maximum angle of the light beam emitted from the projection optics that can still be irradiated on the substrate plane 22A.

In the lithographic projection apparatus, the source provides illumination (ie, radiation) to the patterned device, and the projection optics directs the illumination onto the substrate via the patterned device and shapes the illumination. The projection optics may include at least some of the components 14A, 16Aa, 16Ab, and 16Ac. Aerial image (AI) is the radiation intensity distribution at the level of the substrate. The resist model can be used to calculate the resist image from the aerial image. An example of this can be found in US Patent Application Publication No. US 2009-0157630, the entire disclosure of which is hereby incorporated by reference. The resist model is only related to the properties of the resist layer, such as the effects of chemical processes that occur during exposure, post-exposure bake (PEB), and development. The optical properties of the lithographic projection device (such as the properties of lighting, patterning devices, and projection optics) dictate aerial images and can be defined in the optical model. Since the patterning device used in the lithography projection device can be changed, the optical properties of the patterning device need to be separated from the optical properties of the rest of the lithography projection device including at least the source and projection optics. The details of the technology and model used to transform the design layout to various lithographic images (such as aerial images, resist images, etc.), use their technologies and models to apply OPC, and evaluate performance (such as based on process windows) are described in the U.S. Patent In the application publications US 2008-0301620, 2007-0050749, 2007-0031745, 2008-0309897, 2010-0162197 and 2010-0180251, all the disclosures of the aforementioned cases are hereby incorporated by reference.

One aspect of understanding the lithography process is to understand the interaction between radiation and patterned devices. The electromagnetic field of the radiation after the radiation passes through the patterned device can be determined from the electromagnetic field of the radiation before the radiation reaches the patterned device and the function that characterizes the interaction. This function can be referred to as the mask transmission function (it can be used to describe the interaction of the transmission patterning device and/or the reflection patterning device).

The mask transmission function can have a variety of different forms. One form is binary. The binary mask transmission function has any one of two values (such as zero and a normal number) at any given location on the patterned device. The transmission function of the mask in a binary form can be called a binary mask. The other form is continuous. That is, the modulus of the transmittance (or reflectance) of the patterned device is a continuous function of the position on the patterned device. The transmittance (or reflectance) phase can also be a patterned device Continuous function of the upper part. The transmission function of a mask in a continuous form can be called a continuous tone mask or a continuous transmission mask (CTM). For example, CTM can be expressed as a pixelated image, where a value between 0 and 1 (for example, 0.1, 0.2, 0.3, etc.) can be assigned to each pixel instead of a binary value of 0 or 1. In an embodiment, the CTM may be a pixelated grayscale image, in which each pixel has several values (for example, in the range [-255,255], in the range [0,1] or [-1,1] or other suitable ranges The normalized value).

The thin mask approximation (also known as Kirchhoff boundary condition) is widely used to simplify the determination of the interaction between radiation and patterned devices. The thin mask approximately assumes that the thickness of the structure on the patterned device is extremely small compared to the wavelength, and the width of the structure on the mask is extremely large compared to the wavelength. Therefore, the thin mask approximately assumes that the electromagnetic field after the patterned device is the product of the incident electromagnetic field and the transmission function of the mask. However, when the lithography process uses radiation with shorter and shorter wavelengths, and the structure on the patterned device becomes smaller and smaller, the approximate assumption of the thin mask can be broken. For example, due to the finite thickness of the structure (such as the edge between the top surface and the side wall), the interaction between the radiation and the structure ("mask 3D effect" or "M3D") can become significant. Including this scattering in the mask transmission function allows the mask transmission function to better capture the interaction between the radiation and the patterned device. The transmission function of the mask under the thin mask approximation can be called the transmission function of the thin mask. The mask transmission function covering M3D can be referred to as the M3D mask transmission function.

According to the embodiment of the present invention, one or more images can be generated. The image includes various types of signals that can be characterized by the pixel value or intensity value of each pixel. Depending on the relative value of the pixels in the image, the signal can be called, for example, a weak signal or a strong signal, which can be understood by those familiar with the art. The terms "strong" and "weak" are relative terms based on the intensity value of the pixels in the image, and the specific value of the intensity may not limit the scope of the present invention. In an embodiment, a strong signal and a weak signal can be identified based on the selected threshold value. In an embodiment, the threshold may be fixed (e.g., shadow The midpoint of the highest and lowest intensity of the pixels in the image). In an embodiment, a strong signal may refer to a signal having a value greater than or equal to an average signal value across the image, and a weak signal may refer to a signal having a value less than the average signal value. In an embodiment, the relative intensity value may be based on a percentage. For example, a weak signal may be a signal having an intensity less than 50% of the highest intensity of a pixel in the image (for example, a pixel corresponding to a target pattern may be regarded as a pixel with the highest intensity). In addition, each pixel in the image can be regarded as a variable. According to this embodiment, the derivative or partial derivative can be determined with respect to each pixel in the image, and the value of each pixel can be determined or modified according to the evaluation based on the cost function and/or the gradient-based calculation of the cost function. For example, a CTM image can include pixels, where each pixel is a variable that can take any real value.

FIG. 2 illustrates an exemplary flow chart for simulating lithography in a lithography projection device according to an embodiment. The source model 31 represents the optical characteristics of the source (including radiation intensity distribution and/or phase distribution). The projection optics model 32 represents the optical characteristics of the projection optics (including changes in the radiation intensity distribution and/or phase distribution caused by the projection optics). The design layout model 35 represents the optical characteristics of the design layout (including changes to the radiation intensity distribution and/or phase distribution caused by the design layout), which is the configuration of features on or formed by the patterned device The representation. The self-source model 31, the projection optics model 32, and the design layout model 35 can simulate the aerial image 36. The resist model 37 can be used to simulate the resist image 38 from the aerial image 36. The simulation of lithography can, for example, predict the contour and CD in the resist image.

More specifically, it should be noted that the source model 31 can represent the optical characteristics of the source, including but not limited to numerical aperture setting, illumination mean square deviation (σ) setting, and any specific illumination shape (for example, off-axis radiation source). , Such as loops, quadrupoles, dipoles, etc.). The projection optics model 32 can represent the optical characteristics of the projection optics, and the optical characteristics include aberration, distortion, one or more refractive indexes, one or more physical sizes, one or more physical sizes, and so on. The design layout model 35 may represent one or more physical properties of the physical patterned device, as described in, for example, US Patent No. 7,587,704, which is incorporated by reference in its entirety. The goal of the simulation is to accurately predict, for example, edge placement, aerial image intensity slope and/or CD, and then compare edge placement, aerial image intensity slope and/or CD with the expected design. The prospective design is usually defined as a pre-OPC design layout that can be provided in a standardized digital file format such as GDSII or OASIS or other file formats.

According to this design layout, one or more parts called "clips" can be identified. In an embodiment, a collection of clips is extracted, which represents a complex pattern in the design layout (usually about 50 to 1000 clips, but any number of clips can be used). These patterns or clips represent smaller parts of the design (ie, circuits, cells, or patterns), and more specifically, these clips generally represent smaller parts that require specific attention and/or verification. In other words, the editing can be part of the design layout, or can be similar or similar behaviors that have a part of the design layout, in which one or more critical features are through experience (including editing provided by the customer), trial and error, or execution. Wafer simulation to be identified. The clip may contain one or more test patterns or gauge patterns.

The client can provide an initial larger set of clips a priori based on the known critical feature areas that require specific image optimization in the design layout. Alternatively, in another embodiment, an initial larger set of clips can be extracted from the entire design layout by using some automatic (such as machine vision) or manual algorithm that recognizes the one or more critical feature regions.

In the lithographic projection device, as an example, the cost function can be expressed as

Among them, ( z ₁ , z ₂ ,..., z _N ) are N design variables or their values. f _p ( z ₁ , z ₂ ,…, z _N ) can be a function of design variables ( z ₁ , z ₂ ,…, z _N ), such as design variables for (z ₁ , z ₂ ,…, z _N) The difference between the actual value and the expected value of the characteristic of the value set. w _p is the weight constant associated with f _p ( z ₁ , z ₂ ,..., z _{N ).} For example, the characteristic may be the position of the edge of the pattern measured at a given point on the edge. Different f _p ( z ₁ , z ₂ ,..., z _N ) may have different weights w _p . For example, if a particular edge having a narrow range of positions permitted, is used for f _p represents the difference of the actual position of the edge between the expected position _{(z 1, z 2, ...} , z N) may be the weight w _p Is given a higher value. f _p ( z ₁ , z ₂ ,..., z _N ) can also be a function of inter-layer characteristics, which in turn are functions of design variables ( z ₁ , z ₂ ,..., z _N ). Of course, CF ( z ₁ , z ₂ ,..., z _N ) is not limited to the form in Equation 1. CF ( z ₁ , z ₂ ,..., z _N ) can take any other suitable form.

The cost function can represent any one or more suitable characteristics of the lithography projection device, the lithography process or the substrate, such as focus, CD, image shift, image distortion, image rotation, random change, yield, local CD change , Process window, interlayer characteristics, or a combination thereof. In one embodiment, the design variables ( z ₁ , z ₂ ,..., z _N ) include one or more selected from the group consisting of dose, global bias of the patterned device, and/or illumination shape. Since the resist image often dictates the pattern on the substrate, the cost function may include a function representing one or more characteristics of the resist image. For example, f _p ( z ₁ , z ₂ ,..., z _N ) can only be the distance between one point in the resist image and the expected position of that point (that is, the edge placement error EPE _p ( z ₁ , z ₂ ,…, z _N )). The design variables can include any adjustable parameters, such as adjustable parameters such as source, patterning device, projection optics, dose, focus, etc.

The lithography device may include a component collectively referred to as a "wavefront manipulator" that can be used to adjust the shape of the wavefront and intensity distribution and/or the phase shift of the radiation beam. In an embodiment, the lithography device can be adjusted at any position along the optical path of the lithography projection device (such as before the patterning device, near the pupil plane, near the image plane, and/or near the focus plane). Wave front and intensity distribution. The wavefront manipulator can be used to correct or compensate for certain wavefront and intensity distributions and/or phase shifts caused by, for example, the source, patterned devices, temperature variations in the lithographic projection device, thermal expansion of the components of the lithographic projection device, etc. Some distortion. Adjusting the wavefront and intensity distribution and/or phase shift can be changed by the cost The value of the characteristic represented by the function. Such changes can be simulated from the model or actually measured. The design variables may include the parameters of the wavefront manipulator.

Z，其中Z為設計變數之可能值的集合。可藉由微影投影裝置之所要產出率來強加對設計變數之一個可能約束。在無藉由所要產出率強加之此約束的情況下，最佳化可得到不切實際的設計變數之值集合。舉例而言，若劑量為設計變數，則在無此約束之情況下，最佳化可得到使產出率經濟上不可能的劑量值。然而，約束之有用性不應解釋為必要性。舉例而言，產出率可受光瞳填充比影響。對於一些照明設計，低光瞳填充比可捨棄輻射，從而導致較低產出率。產出率亦可受到抗蝕劑化學反應影響。較慢抗蝕劑(例如要求適當地曝光較高量之輻射的抗蝕劑)導致較低產出率。 Design variables can have constraints, which can be expressed as ( z ₁ , z ₂ ,…, z _N )

Z , where Z is the set of possible values of design variables. A possible constraint on design variables can be imposed by the desired output rate of the lithographic projection device. Without imposing this constraint by the desired output rate, optimization can result in an unrealistic set of values of design variables. For example, if the dose is a design variable, without this constraint, optimization can obtain a dose value that makes the output rate economically impossible. However, the usefulness of constraints should not be interpreted as necessity. For example, the output rate can be affected by the pupil filling ratio. For some lighting designs, low pupil filling ratios can discard radiation, resulting in lower yields. The yield can also be affected by the chemical reaction of the resist. Slower resists (e.g., resists that require proper exposure to higher amounts of radiation) result in lower yields.

As used herein, the term "patterning process" means a process of producing an etched substrate by applying a specified pattern of light as part of the lithography process.

As used herein, the term "imaging device" means any number of devices and associated computer hardware and software, or any combination of devices and associated computer hardware and software, which can be configured to produce an image of the target (Such as a printed pattern or part thereof) or an image of any surface and feature as described throughout the specification. Non-limiting examples of imaging devices may include: scanning electron microscope (SEM), atomic force microscope (AFM), x-ray machine, optical microscope, and the like.

Some photolithography processes include, for example, the use of a reduction mask (or mask) to provide a specific pattern of light at the photoresist to produce a pattern for etching onto the wafer. In order to hold the zoom mask and the wafer in place, clamping devices can be used. Because the surface involved is extremely flat for the manufacturing process, the undesired result can be that the shrinking mask can be attached to the shrinking mask fixture, crystal The circle can be attached to a wafer jig or wafer table where wafers are placed. This adhesion can cause damage to wafers, shrinking masks, fixtures, etc. The adhesion mechanism may include forming a van der Waals bond between the components along the contact surface. Therefore, the embodiments of the disclosed subject matter additionally solve the problem of adhesion by, for example, reducing the contact area between components to weaken the total Van der Waals force between objects, so that adhesion is unlikely to occur.

One way to reduce the contact surface area is to make the contact surface rougher so that only the higher part of the roughened surface comes into contact with the wafer or the reduction mask. As described further below, the surface to be roughened is made of a combination of crystalline and amorphous materials. As an example, a laser can be used to deliver a specific amount of energy to the surface so that amorphous material can be ablated, while crystalline material is not ablated or is ablated significantly less. This selective ablation reduces the contact surface area by allowing only the wafer or the reduction mask to contact the remaining crystalline material. By changing the laser energy and the mode of laser delivery to the surface, different degrees of roughness and roughness patterns can be formed.

3 is a simplified top view of a wafer 310 placed on a nodule surface 340 of a wafer table 320 according to an embodiment.

The wafer table 320 is shown as having several nodules 330 combined to form nodules 340. The example wafer 310 is placed on the nodule surface 340. As further explained in FIG. 4, the nodules as used herein may include extensions from a substrate (such as wafer table 320, wafer holder, reduction mask holder, etc.) to support wafer 310 or reduction mask Any material characteristics.

The nodules can provide some nominal separation distance (and reduction in contact surface area) between the wafer 310 and the wafer table 320. For example, by supporting the wafer 310 on the nodule surface 340 (which may be composed of several nodules 330 with a certain distance therebetween), the Van der Waals force described above can be reduced and avoided Vacuum, air bag, etc.

The embodiments described herein generally refer to wafers placed on a wafer table. However, this description is not intended to be limiting. For example, instead of wafers and wafer tables, the aspect of the present invention can also be applied to other components (such as the shrinking mask in contact with the shrinking mask fixture) and to be placed on the surface of the associated nodules. Wafers on nodules of any type, number and geometry.

Figure 4 illustrates a simplified side view of a nodule 330 with a coating 420 according to an embodiment.

The side view illustrated in FIG. 4 shows several exemplary nodules 330 extending from the base plate 410. In some embodiments, as shown, the nodule 330 may include a coating 420 disposed on at least the top surface of the nodule 330, which may be a hard ceramic coating. The coating 420 may include, for example, titanium nitride (TiN), chromium nitride (CrN), diamond-like carbon (DLC), tantalum (Ta), tantalum boride (TaB), tungsten (W), tungsten carbide (WC), Boron nitride (BN) and so on. Such coatings can be added to the nodule 330 to protect the underlying nodule structure. As used herein, the term "nodule surface" (for example, the nodule surface 430 in FIG. 4) can refer to the top surface of the nodule 330 when the coating 420 is not present, or that the coating 420 is present on the nodule 330 on the top surface of the coating 420.

As discussed throughout the present invention, a surface that is a candidate for roughening may include the top of a nodule (such as the substrate of the nodule itself) that can exhibit adhesion during use, a coating, or any other suitable surface. Figure 5 illustrates a side view of the top of an example tumor section. An expanded part of the cross section of the nodule is shown on the upper left. As described herein, some materials may have portions that are easier to remove (such as by laser ablation) than others. For example, the illustrated nodule coating may have a semi-crystalline structure, which may include crystalline grains 510 and a softer material between the crystalline grains (referred to herein as crystalline grain boundaries 520). In Figure 5, the bright vertical band is a simplified representation of hard crystal grains, and the dark vertical band is a simplified representation of softer crystal grain boundaries.

A further expanded view of a part of the nodule section is shown in the upper right part of FIG. 5, which illustrates an example of vertical crystal grains 510 (lightly colored) and crystal grain boundaries 520 (darkly colored and located between crystal grains 510) Transmission electron microscope image.

As used herein, the term "native surface" means the surface that exists before a given roughening process (which produces the "modified surface" discussed below). A simplified example of the native surface 530 is illustrated by the dashed line in the simplified cross-sectional view of the top of the nodule.

6 and 7 illustrate a method for reducing the adhesion of an object (such as a reduction mask) to a modified surface (for example, for example, the roughened surface of the reduction mask fixture illustrated in FIG. 7). In some cases, this can be a modified surface used to support objects in the lithography process. As shown in FIG. 6, an example method of reducing adhesion may include controlling a light source (e.g., a laser) to deliver light 620 to a native surface 610 (e.g., a portion of the top surface of a nodule), thereby making at least a portion of the native surface The ablation of a portion increases the roughness of the original surface, thereby forming a modified surface (for example, as shown in FIG. 7). Because cutting off a part of the surface that can come into contact with the object can reduce the contact surface area, the increased roughness reduces the ability of the object to adhere to the modified surface.

As used herein, the term "modified surface" means a surface that has been roughened relative to the previous state by any of the methods disclosed herein. For the sake of simplicity, the present invention often refers to a "primary surface" that has been roughened to become a modified surface. However, the modified surface can also be produced from any surface that has been treated by the disclosed method or by other methods. For example, multiple applications of the roughening process described herein can produce a modified surface, where the surface is first modified (roughened) and then roughened again to form another modified surface. In addition, as another example, the surface can be cut, ground, sandblasted, etc. before applying the disclosed method to "modify" any of the initial or "native" surfaces.

Because the original surface can include the grain boundary by selecting the light source (the light source cuts the grain boundary But it is not enough to remove the crystal grains separated by the energy density of the crystal grains, so the selective removal of the primary surface with the effect of roughening the primary surface can be performed.

Therefore, some embodiments may include setting the energy density of the light source to generate light with flux at the primary surface, which when delivered to the surface results in selective ablation of the primary surface based on the atomic structure of the primary surface. In this way, selective ablation can reduce the surface area used to contact the object, and thereby reduce the adhesion between the object and the modified surface.

This can be performed by, for example, removing the material of the grain boundary while substantially not causing the ablation of the crystal grains. As used herein, when it is described that there is "substantially" no removal of crystal grains, this is meant to mean that the removal of crystal grains is significantly less than the removal of grain boundaries. For example, the completed amount of crystal grains may be less than 10% of the corresponding removal of the crystal grain boundary of the same energy density receiving light or less than 1% of the corresponding removal of the crystal grain boundary of the same energy density receiving light.

The present invention covers different methods by which the energy density used for ablation can be set. For example, the light source can be controlled to adjust one or more of the intensity and/or focus of the light source to set the energy density based on the desired roughness of the modified surface. The adjustment and intensity of the light source can include increasing the power of the light source and adding additional light sources to combine light at the modified surface.

As illustrated in FIG. 6, the focal point 630 of the light source can be adjusted (e.g., increased or decreased) such that the light spot formed by the change of the light source, thereby increasing or decreasing the energy density. As used herein, the term "focus" means the degree to which the light source is focused at the native surface. Generally speaking, when most of the light from the light source is focused on the surface, the energy density is maximum. In the example of FIG. 6, where the position of the surface moves relative to the light source (by moving the nodule/nodule surface or by moving the lens 612), the focus will change. In addition, as shown, the light source is slightly out of focus, resulting in an energy density that will be less than the maximum density if the surface is at the illustrated focal point. The focus is also related to the size of the light spot. This is because generally speaking, when the light source is focused on the surface, the The light spot size is the smallest.

In addition, as used herein, when referring to "light source", it should be understood that this includes not only the laser source itself, but also any intervening optical elements between the laser source and the surface. Such optical elements may include, for example, mirrors, filters, lenses, and the like.

Figure 7 illustrates a simplified example of a modified surface 710 produced by the roughening method described herein. Fig. 7 is similar to Fig. 6 and shows an exemplary section of the light source 610 and the top of the nodule. However, the example shown illustrates the grain boundary material 520 that is cut away, and therefore the modified surface 710 has some portions below the initial native surface 530.

The surface described herein can be formed on an object or device used in the lithography process, but can also be formed on any other object or device used for applications that can benefit from the disclosed method. Thus, the modified surface can be part of the device, where the modified surface can be configured to contact an object. The modified surface of the device can be formed of a material having a grain structure including crystal grains and grain boundaries. As shown in FIG. 7, the modified surface may have a roughness based at least on crystal grain peaks and crystal grain boundary valleys located below the crystal grain peaks. In the specific example shown in FIG. 6, prior to roughening, the native surface 530 has a region including both crystal grains and grain boundaries (although shown from the side and indicated by dashed lines). In FIG. 7, after roughening, some grain boundary material has been removed, thereby forming crystal grain peaks 720 and crystal grain boundary valleys 730. Thus, the modified surface 710 (again indicated by the dashed line) of the object that will be in contact does not include crystalline grain boundary materials (e.g., crystalline grain boundary valleys 730). Therefore, in general, the contact surface area at the modified surface can be smaller than its contact surface area before the roughening process.

The lower part of FIG. 7 illustrates an example of a TEM image corresponding to the schematic diagram of the upper part of FIG. 7. Here, the lighter coloring material represents the crystalline grain 510 (which has a columnar structure in this example). As can be seen, some materials (such as grain boundary materials) have moved from between the crystal grains. remove. Therefore, the increase in roughness is evident in this image and the reduced contact surface area of the modified surface.

In some embodiments, at at least one location on the modified surface, the grain boundary material between 2 nm and 30 nm is removed from the original surface. In addition, in other embodiments, the modified surface may include roughened areas in which about 5 nm of material in at least one of the grain boundaries has been removed. In still other embodiments, the modified surface may have an arithmetic mean height (Sa) between 0.4 nm and 19 nm. As used herein, "roughness" can refer to the arithmetic average height or the RMS roughness of a portion of the modified surface.

In some embodiments, the roughness may be the root mean square of the height of the modified surface, and may be between 3 nm and 35 nm, or between 20 nm and 35 nm. Therefore, in various embodiments, the roughness of the modified surface can be greater than 2 nm, and the roughness of the original surface can be less than 3 nm.

Since the ablation of the grain boundary material can be a function of the energy density of the light delivered at the surface, the surface roughness can be expressed in terms of the energy density ratio. Specifically, in some examples, an energy density ratio of 1.0 (for a given light source output, spot size, etc.) can produce a surface roughness of approximately 20 nm, an energy density ratio of 1.05 can produce a surface roughness of approximately 25 nm, and 1.15 The energy density ratio produces a surface roughness of approximately 30nm.

The roughening process described herein can produce several suitable devices that exhibit reduced adhesion. For example, the device may include a plurality of nodules extending from a substrate (such as a shrinking mask holder, a wafer holder, or a wafer table), wherein the modified surface is located on the top surface of the nodules. In such embodiments, the nodule can be, for example, Si or SiC, and optionally has a coating (such as Ti, Cr, or DLC) that is applied to the top surface of the nodule so that the modified surface can be Formed in the coating to reflect the roughened nodules under the coating.

In other embodiments of the present invention, roughening can be applied to various patterns at a certain macro-scale. This can be regarded as "low frequency roughening", which is contrary to the "high frequency roughening" which will more describe the smaller-scale ablation area caused by the removal of crystalline grain boundary material. The low-frequency roughening can be performed by controlling the light source to deliver light at the separation site 810 that results in the ablation of a part of the grain boundary on the native surface. In this way, light delivery can cause the modified surface to include roughened areas with a distance of 820 therebetween. These separated roughened areas (shown by the gray bands in FIG. 8) can take the form of, for example, a series of parallel lines, intersecting lines (for example, similar to a checkerboard pattern), spiral patterns, and the like. An example of such a separation site is illustrated on the example tumor node shown in FIG. 8.

In some embodiments, the nodule 330 may (for example, it is a part of a zoom mask holder) includes a hillock 830 formed on the nodule 330 or the nodule coating. The hillocks formed in the nodules can be, for example, about 10 μm wide, spaced 10 μm apart from each other, and have a height between 80 nm and 120 nm. In this example, the light source can be controlled to deliver light across the hilltop of the hillock formed on the top surface of the nodule, thereby forming a modified surface on the hillock. As used with regard to the delivery of light across the top of the hillock (or any other feature of the nodule), the term "across" means a direction generally perpendicular to the hillock. However, in other embodiments, the approximate angle of the light path may be, for example, 90 degrees, 80 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees, and so on. In this way, the light path across the hilltops formed in the surface can potentially intersect multiple hilltops to form secondary roughening features. In still other embodiments, roughening may be performed on the top of the hillock (for example, substantially parallel to the top of the hillock) in order to increase the roughened area as described herein.

The distance between the roughened areas can be changed. In some embodiments, the distance between the roughened regions on the modified surface may be about 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, or 30 μm. As illustrated in Figure 8, the separation distance 820 can be greater than the light spot size of the light source (from the gray The width of the band is indicated) so that the roughened areas do not overlap. In other embodiments, the distance between the light-delivery parts may be smaller than the light spot size of the light source, which may cause a certain degree of overlap of the light-receiving parts. In such embodiments, for example, due to the multiple application of energy to the grain boundary material at their overlapping regions, there may be additional roughening in the overlapping regions.

When the embodiments of the present invention are discussed with reference to a material having a crystalline structure (the crystalline structure has soft crystal grain boundaries suitable for removal), the method and the resulting device described herein can be used with other materials and can be used in other applications middle. For example, the material need not have a strictly crystalline structure. In fact, any suitable material that permits better or selective removal of certain areas when exposed to light can be used, or the material can be the recipient of the disclosed method.

By applying the methods described herein, the roughness of the surface (such as the top of the nodule) can be engineered by applying light control to the native surface. As previously discussed, this can be a function of the distance or line spacing between the parts delivering light, and b) the energy density of the light at the primary surface. This can basically provide a roughness map that can be delivered after executing specific programming instructions on the light source. A simplified example of this roughness map is illustrated in FIG. 9. The roughness is schematically represented by shading, and in this example, the roughness is in the range of Sa of 2 nm to 15 nm. As shown, the roughness increases as the line spacing decreases (when there are fewer gaps between the roughened areas). In addition, the roughness increases as the energy density increases (when more crystal grain boundaries are removed). In this way, consistent with certain aspects of the present invention, the roughness can be selected by the user, and the distance between the roughened areas and the energy density delivered by the light source can be specified. There may be similar roughness maps produced for different nodule materials, different coatings, etc. Therefore, considering the variation of the example roughness map, the specific roughness value and the distance between the indicated light delivery should not be considered as a limitation.

Reduce the effect of the object on the modified surface (e.g., for support in the lithography process An example method 1010 of the attachment of parts) is illustrated in FIG. 10. In this embodiment, the method includes controlling the light source to deliver light to the original surface, thereby causing the removal of at least a portion of the original surface to increase the roughness of the original surface, thereby forming a modified surface, wherein the increased roughness Reduce the ability of the object to adhere to the modified surface.

FIG. 11 is a block diagram of an example computer system CS according to an embodiment. The computer system CS includes a bus BS or other communication mechanism for communicating information, and a processor PRO (or multiple processors) coupled with the bus BS for processing information. The computer system CS also includes a main memory MM, such as a random access memory (RAM) or other dynamic storage devices, which is coupled to the bus BS for storing information and instructions to be executed by the processor PRO. The main memory MM can also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by the processor PRO. The computer system CS further includes a read-only memory ROM or other static storage device coupled to the bus BS for storing static information and instructions for the processor PRO. Provide a storage device SD such as a magnetic disk or an optical disk, and couple it to the bus BS for storing information and commands.

The computer system CS can be coupled to a display DS for displaying information to the computer user via the bus BS, such as a cathode ray tube (CRT) or a flat panel display or a touch panel display. The input device ID including the alphanumeric keys and other keys is coupled to the bus BS for transmitting information and command selection to the processor PRO. Another type of user input device is a cursor control element CC for transmitting direction information and command selection to the processor PRO and for controlling the movement of the cursor on the display DS, such as a mouse, a trackball or a cursor direction button. This input device usually has two degrees of freedom in two axes (a first axis (for example x) and a second axis (for example y)), which allows the device to specify a position in a plane. The touch panel (screen) display can also be used as an input device.

According to one embodiment, part of one or more of the methods described herein may be executed by the computer system CS in response to the processor PRO to execute one or more sequences of one or more instructions contained in the main memory MM. Such instructions can be read into the main memory MM from another computer-readable medium (such as the storage device SD). Executing the instruction sequence contained in the main memory MM causes the processor PRO to execute the process steps described herein. One or more processors in a multi-processing configuration can also be used to execute the sequence of instructions contained in the main memory MM. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software commands. Therefore, the description in this article is not limited to any specific combination of hardware circuit system and software.

The term "computer-readable medium" as used herein refers to any medium that participates in providing instructions to the processor PRO for execution. This media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical disks or magnetic disks, such as storage devices SD. Volatile media includes dynamic memory, such as main memory MM. Transmission media includes coaxial cables, copper wires and optical fibers, including wires including bus bars BS. The transmission medium can also take the form of sound waves or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Computer-readable media can be non-transitory, such as floppy disks, flexible disks, hard disks, tapes, any other magnetic media, CD-ROM, DVD, any other optical media, punch cards, paper tape, Any other physical media with hole patterns, RAM, PROM and EPROM, FLASH-EPROM, any other memory chips or cassettes. The non-transitory computer-readable medium may have instructions recorded on it. These instructions, when executed by a computer, can implement any of the features described herein. Transitory computer-readable media may include carrier waves or other propagated electromagnetic signals.

Various forms of computer-readable media may involve carrying one or more sequences of one or more instructions to the processor PRO for execution. For example, these instructions can initially be carried On the disk of the remote computer. The remote computer can load commands into its dynamic memory, and use a modem to send commands through the telephone line. The modem at the local end of the computer system CS can receive the data on the telephone line, and use an infrared transmitter to convert the data into an infrared signal. The infrared detector coupled to the bus BS can receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries data to the main memory MM, and the processor PRO retrieves and executes commands from the main memory MM. The instructions received by the main memory MM may be stored on the storage device SD before or after being executed by the processor PRO as appropriate.

The computer system CS may also include a communication interface CI coupled to the bus BS. The communication interface CI provides a two-way data communication coupling with the network link NDL, which is connected to the local area network LAN. For example, the communication interface CI can be an integrated services digital network (ISDN) card or a modem to provide a data communication connection with a corresponding type of telephone line. As another example, the communication interface CI may be a local area network (LAN) card to provide a data communication connection with a compatible LAN. A wireless link can also be implemented. In any such implementation, the communication interface CI sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.

The network link NDL usually provides data communication to other data devices via one or more networks. For example, the network link NDL can provide a connection to the host computer HC via a local area network LAN. This may include data communication services provided via the global packet data communication network (now commonly referred to as the "Internet" INT). Local area network LAN (Internet) uses electrical, electromagnetic or optical signals that carry digital data streams. The signals through various networks and the signals on the network data link NDL and through the communication interface CI are exemplary forms of carrier waves for conveying information. These signals carry digital data to and from the computer system CS. Load digital data.

The computer system CS can pass through the network, network data link NDL and communication interface CI sends messages and receives data (including code). In the Internet example, the host computer HC can transmit the requested code for the application program via the Internet INT, the network data link NDL, the local area network LAN, and the communication interface CI. For example, one such downloaded application can provide all or part of the methods described herein. The received program code can be executed by the processor PRO when it is received, and/or stored in the storage device SD or other non-volatile storage for later execution. In this way, the computer system CS can obtain application code in the form of a carrier wave.

Fig. 12 is a schematic diagram of a lithography projection apparatus according to an embodiment.

The lithography projection device may include an illumination system IL, a first object table MT, a second object table WT, and a projection system PS.

The illumination system IL can adjust the radiation beam B. In this particular situation, the lighting system also includes a radiation source SO.

The first object stage (for example, the patterned device stage) MT can be provided with a patterned device holder for holding the patterned device MA (for example, a reduction mask), and is connected to accurately position the patterned device relative to the item PS The first locator of the device.

The second object table (substrate table) WT can be provided with a substrate holder for holding the substrate W (for example, a resist-coated silicon wafer), and is connected to a second positioner for accurately positioning the substrate relative to the item PS .

The projection system ("lens") PS (such as a refractive, reflective, or catadioptric optical system) can image the irradiated portion of the patterned device MA onto the target portion C (such as containing one or more dies) of the substrate W.

As depicted herein, the device may be of the transmissive type (ie, have a transmissive patterned device). However, generally speaking, it can also be of the reflective type (with reflective patterned devices), for example. The device can use different types of patterned devices from classic masks; examples include programmable Mirror array or LCD matrix.

The source SO (for example, mercury lamp or excimer laser, laser generating plasma (LPP) EUV source) generates a radiation beam. For example, this light beam is fed into the lighting system (illuminator) IL either directly or after having traversed an adjustment device such as a beam expander BD. The illuminator IL may include an adjustment device AD for setting the outer radial range and/or the inner radial range of the intensity distribution in the beam (usually referred to as σouter and σinner, respectively). In addition, the illuminator IL will generally include Various other components, such as the integrator IN and the condenser CO. In this way, the beam B irradiated on the patterned device MA has the desired uniformity and intensity distribution in its cross section.

In some embodiments, the source SO may be in the housing of the lithography projection device (as is often the case when the source SO is, for example, a mercury lamp), but it can also be far away from the lithography projection device, and the radiation beam generated by the source SO (such as It is guided into the device by means of a suitable guide mirror; the latter case may be the case when the source SO is an excimer laser (for example, a laser based on KrF, ArF, or F2).

The light beam PB can then intercept the patterned device MA held on the patterned device table MT. Having traversed the patterned device MA, the light beam B can pass through the lens PL, which focuses the light beam B onto the target portion C of the substrate W. With the aid of the second positioning device (and the interferometric measuring device IF), the substrate table WT can be accurately moved, for example, to position different target parts C in the path of the light beam PB. Similarly, the first positioning device can be used to accurately position the patterned device MA relative to the path of the beam B, for example, after the patterned device MA is mechanically retrieved from the patterned device library or during scanning. Generally speaking, a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) can be used to realize the movement of the object table MT and WT. However, in the case of a stepper (as opposed to a step-and-scan tool), the patterned device table MT may be connected to a short-stroke actuator only, or may be fixed.

Can be used in two different modes (step mode and scan mode) tool. In the stepping mode, the patterned device stage MT is kept substantially still, and the entire patterned device image is projected onto the target portion C at one time (that is, a single "flash"). The substrate table WT can be shifted in the x and/or y direction so that different target portions C can be irradiated by the light beam PB.

In the scanning mode, except that the given target portion C is not exposed in a single "flash", basically the same situation applies. In fact, the patterned device stage MT can move at a speed v in a given direction (the so-called "scanning direction", for example, the y direction), so that the projection beam B scans on the patterned device image; at the same time, the substrate stage WT moves simultaneously in the same or opposite directions at a speed of V=Mv, where M is the magnification of the lens PL (usually, M=1/4 or 1/5). In this way, a relatively large target portion C can be exposed without compromising the resolution.

FIG. 13 is a schematic diagram of another lithographic projection apparatus (LPA) according to an embodiment.

The LPA may include a source collector module SO, an illumination system (illuminator) IL configured to adjust the radiation beam B (for example, EUV radiation), a support structure MT, a substrate table WT, and a projection system PS.

The support structure (e.g., patterned device stage) MT may be constructed to support the patterned device (e.g., mask or resize mask) MA, and is connected to a first positioner PM configured to accurately position the patterned device.

The substrate table (e.g., wafer table) WT may be configured to hold a substrate (e.g., a resist coated wafer) W, and is connected to a second positioner PW configured to accurately position the substrate.

The projection system (e.g., reflective projection system) PS may be configured to project the pattern imparted to the radiation beam B by the patterning device MA onto the target portion C (e.g., including one or more dies) of the substrate W.

As depicted here, LPA can be of a reflective type (e.g. using a reflective patterner Pieces). It should be noted that because most materials are absorptive in the EUV wavelength range, the patterned device may have a multilayer reflector including many stacks of molybdenum and silicon, for example. In one example, the multi-stack reflector has 40 layer pairs of molybdenum and silicon, where the thickness of each layer is a quarter wavelength. X-ray lithography can be used to generate even smaller wavelengths. Since most materials are absorptive at EUV and X-ray wavelengths, a thin piece of patterned absorbing material (such as a TaN absorber on top of a multilayer reflector) defining features on the patterned device configuration will be printed ( Positive resist) or not printed (negative resist).

The illuminator IL can receive the extreme ultraviolet radiation beam from the source collector module SO. Methods for generating EUV radiation include, but are not necessarily limited to, using one or more emission lines in the EUV range to convert a material into a plasma state with at least one element (for example, xenon, lithium, or tin). In one such method (often referred to as laser-generated plasma ("LPP")), a laser beam can be used to irradiate fuel (such as droplets, streams, or clusters of materials with line-emitting elements). ) To generate plasma. The source collector module SO may be part of an EUV radiation system including a laser used to provide a laser beam for exciting fuel. The resulting plasma emits output radiation (such as EUV radiation), and a radiation collector arranged in the source collector module is used to collect the output radiation. For example, when a CO2 laser is used to provide a laser beam for fuel excitation, the laser and the source collector module can be separate entities.

In such cases, the laser may not be considered to form part of the lithography device, and the radiation beam may be transmitted from the laser to the source collector by means of a beam delivery system including, for example, a suitable guide mirror and/or beam expander Module. In other cases, for example, when the source is a discharge generating plasma EUV generator (often referred to as a DPP source), the source may be an integral part of the source collector module.

The illuminator IL may include adjustments for adjusting the angular intensity distribution of the radiation beam Device. Generally speaking, at least the outer radial extent and/or the inner radial extent (usually referred to as σouter and σinner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. In addition, the illuminator IL may include various other components, such as a faceted field mirror device and a faceted pupil mirror device. The illuminator can be used to adjust the radiation beam to have the desired uniformity and intensity distribution in its cross section.

The radiation beam B can be incident on a patterned device (such as a mask) MA held on a support structure (such as a patterned device table) MT and patterned by the patterned device. After being reflected from the patterned device (eg, mask) MA, the radiation beam B passes through the projection system PS, which focuses the beam onto the target portion C of the substrate W. With the aid of the second positioner PW and the position sensor PS2 (for example, an interferometric measuring device, a linear encoder or a capacitive sensor), the substrate table WT can be accurately moved, for example, to position different target parts C in the radiation beam In the path of B. Similarly, the first positioner PM and the other position sensor PS1 can be used to accurately position the patterned device (such as a mask) MA relative to the path of the radiation beam B. The patterned device alignment marks M1, M2 and the substrate alignment marks P1, P2 can be used to align the patterned device (for example, the mask) MA and the substrate W.

The depicted device LPA can be used in at least one of the following modes: step mode, scan mode, and static mode.

In the stepping mode, when the entire pattern imparted to the radiation beam is projected onto the target portion C at one time, the support structure (such as the patterned device table) MT and the substrate table WT are kept substantially stationary (that is, a single shot). Static exposure). Next, the substrate table WT is shifted in the X and/or Y direction, so that different target portions C can be exposed.

In the scanning mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the support structure (for example, the patterned device stage) MT and the substrate stage WT are simultaneously scanned (ie, a single dynamic exposure). The magnification (reduction rate) and image reversal feature of the projection system PS can be used To determine the speed and direction of the substrate table WT relative to the support structure (for example, the patterned device table) MT.

In the stationary mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the support structure (such as the patterning device table) MT is kept substantially stationary to hold the programmable patterned device, and the substrate is moved or scanned Taiwan WT. In this mode, a pulsed radiation source is usually used, and the programmable patterned device is updated as needed after each movement of the substrate table WT or between successive radiation pulses during scanning. This mode of operation can be easily applied to unmasked lithography using programmable patterned devices (such as programmable mirror arrays).

Fig. 14 is a detailed view of the lithography projection apparatus according to an embodiment.

As shown, the LPA may include a source collector module SO, an illumination system IL, and a projection system PS. The source collector module SO is constructed and configured such that a vacuum environment can be maintained in the enclosure structure ES of the source collector module SO. The EUV radiation emitting thermoplasma HP can be formed by generating a plasma source by discharge. The EUV radiation can be generated by gas or steam (such as Xe gas, Li steam or Sn steam), in which thermoplasma HP is generated to emit radiation in the EUV range of the electromagnetic spectrum. For example, the thermoplasma HP is generated by generating discharge of at least part of ionized plasma. In order to efficiently generate radiation, Xe, Li, Sn steam or any other suitable gas or steam at a partial pressure of, for example, 10 Pa may be required. In an embodiment, an excited tin (Sn) plasma is provided to generate EUV radiation.

The radiation emitted by the thermoplasma HP passes through the optional gas barrier or pollutant trap CT (in some cases, also called pollutant barrier or foil trap) positioned in or behind the opening in the source chamber SC器) from the source chamber SC to the collector chamber CC. The contaminant trap CT may include a channel structure. The pollutant trap CT can also include a gas barrier or a combination of a gas barrier and a channel structure. As known in the art, the pollution indicated further in this article The material trap or contaminant barrier CT includes at least a channel structure.

The collector chamber CC may include a radiation collector CO, which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side US and a downstream radiation collector side DS. The radiation traversing the radiation collector CO can be reflected from the grating spectral filter SF to be focused in the virtual source point IF along the optical axis indicated by the dotted dotted line "O". The virtual source point IF may be referred to as an intermediate focus, and the source collector module may be configured such that the intermediate focus IF is located at or near the opening OP in the enclosure structure ES. The virtual source point IF is the image of the radiation emission plasma HP.

Subsequently, the radiation traverses the illumination system IL, which may include a faceted field mirror device FM and a faceted pupil mirror device PM. The faceted field mirror device FM and the faceted pupil mirror device pm It is configured to provide the desired angular distribution of the radiation beam B at the patterned device MA and the desired uniformity of the radiation amplitude at the patterned device MA. After reflecting the radiation beam B at the patterned device MA held by the support structure MT, a patterned beam PB is formed, and the patterned beam PB is imaged to the substrate held by the substrate table WT by the projection system PS through the reflective element RE W up.

More elements than shown can generally be present in the illumination optics unit IL and the projection system PS. Depending on the type of lithography device, a grating spectral filter SF may be present. In addition, there may be more mirrors than those shown in the figures, for example, there may be 1 to 6 additional reflective elements in the projection system PS.

The collector optics CO can be a nested collector with a grazing incidence reflector GR, which is only an example of a collector (or collector mirror). The grazing incidence reflector GR is arranged to be axially symmetrical about the optical axis O, and this type of collector optics CO can be used in combination with a discharge-generating plasma source often referred to as a DPP source.

FIG. 15 is a source collector module SO of the lithographic projection apparatus LPA according to an embodiment Detailed view.

The source collector module SO can be part of the LPA radiation system. Laser LA can be configured to deposit laser energy into fuels such as xenon (Xe), tin (Sn), or lithium (Li), thereby generating highly ionized electricity with an electron temperature of tens of electron volts (eV) Pulp HP. The high-energy radiation generated during the de-excitation and recombination of the plasma is emitted from the plasma, collected by the near-normal incidence collector optics CO, and focused on the opening OP in the enclosure structure ES.

The following items can be used to further describe the embodiments:

1. A method for reducing the adhesion of an object to a modified surface for supporting the object in a lithography process, the method comprising: controlling a light source to deliver light to a native Surface, whereby the excision of at least a portion of the original surface increases the roughness of the original surface, thereby forming the modified surface, wherein the increased roughness reduces the ability of the object to adhere to the modified surface.

2. The method of clause 1, wherein the light source is a laser.

3. The method of clause 1, wherein the primary surface includes a top surface of a nodule.

4. The method of clause 1, wherein the control includes: setting an energy density of the light source to generate light with a flux at the primary surface, and the light is based on an atom of the primary surface when delivered to the surface The structure results in selective ablation of the native surface, which reduces a surface area for contact with the object.

5. The method of clause 4, wherein the primary surface includes crystal grains separated by grain boundaries, wherein the selective ablation removes the material of the grain boundaries and does not substantially result in the removal of the crystal grains.

6. The method of clause 4, the controlling further comprising: adjusting one or more of an intensity and/or focus of the light source to set the energy density based on a desired roughness of the modified surface.

7. The method of clause 1, the control further comprising: delivering light at a separation site on the primary surface that results in the excision of a part of the grain boundaries, the delivery causing the modified surface to include a distance between them Roughened area.

8. The method of clause 7, wherein the separation distance is greater than the size of a spot of the light source.

9. The method of clause 1, wherein a distance between the light delivery positions may be smaller than the size of a light spot of the light source.

10. The method of clause 1, wherein the light delivery spans a plurality of hilltops, and the hillocks are located on a top surface of a nodule forming part of the double-reduction mask holder.

11. A non-transitory machine-readable medium storing instructions that when executed by at least one programmable processor cause the at least one programmable processor to perform operations, the operations including: controlling a light source to Light is delivered to a native surface, whereby the excision of at least a portion of the native surface increases the roughness of the native surface, thereby forming a modified surface, wherein the increased roughness reduces the adhesion of an object to the modified surface Sexual surface ability.

12. The non-transitory machine-readable medium of clause 11, wherein the control includes: setting an energy density of the light source to generate light with a flux at the primary surface, the light being delivered to the surface based on An atomic structure of the primary surface results in selective ablation of the primary surface, and the selective ablation reduces a surface area used to contact the object.

13. The non-transitory machine-readable medium of clause 12, the control further comprising: adjusting one or more of the intensity and/or focus of the light source to set the modified surface based on a desired roughness Energy Density.

14. The non-transitory machine-readable medium of clause 11, the control further comprising: delivering at a separation site on the primary surface that causes a part of the grain boundaries to be cut off Light, the delivery causes the modified surface to include roughened areas with a distance therebetween.

15. A device comprising: a modified surface configured to contact an object, the modified surface being formed of a material including a crystal grain structure including crystal grains and grain boundaries, The modified surface has a roughness at least based on a plurality of crystal grain peaks and a plurality of crystal grain boundary valleys located below the crystal grain peaks.

16. The device of clause 15, wherein the roughness is the root mean square of the height of the modified surface.

17. The device of clause 16, wherein the roughness is between 3 nm and 35 nm.

18. The device of clause 16, wherein the roughness is between 20 nm and 35 nm.

19. The device of clause 16, wherein the roughness of the modified surface is greater than 2 nm.

20. The device of clause 16, wherein the roughness of the native surface is less than 3 nm.

21. The device of clause 15, wherein at at least one location on the modified surface, grain boundary material between 2 nm and 30 nm is removed from the primary surface.

22. The device of clause 15, further comprising a plurality of nodules extending from a substrate, wherein the modified surface is located on the top surface of the plurality of nodules.

23. The device of clause 22, wherein the substrate is a double-reduction mask holder, a wafer holder or a wafer table.

24. The device of clause 22, further comprising a coating on the top surfaces of the nodules, and the modified surface is formed in the coating.

25. The device of clause 24, wherein the coating is a TiN, CrN or DLC coating.

26. The device of clause 22, wherein the plurality of nodules include a plurality of hillocks, and the modified surface is located on the plurality of hillocks.

27. The device of clause 26, wherein the modified surface includes a plurality of roughened areas formed across the hillocks.

28. The device of clause 15, wherein the modified surface includes roughened areas with a distance therebetween.

29. The device of clause 28, wherein the distance between the roughened areas is about 10 microns.

30. The device of clause 28, wherein the distance between the roughened areas is about 15 microns.

31. The device of clause 28, wherein the distance between the roughened areas is about 20 microns.

32. The device of clause 28, wherein the modified surface has an arithmetic mean height (Sa) between 0.4 nm and 19 nm.

33. The device of clause 15, wherein the modified surface includes a roughened area, wherein approximately 5 nm of material in at least one of the grain boundaries has been removed.

The concepts disclosed herein can simulate or mathematically model any general imaging system for imaging sub-wavelength features, and can be particularly applicable to emerging imaging technologies capable of generating shorter and shorter wavelengths. Emerging technologies that are already in use include extreme ultraviolet (EUV) and DUV lithography that can generate 193nm wavelengths by using ArF lasers and even 157nm wavelengths by using fluorine lasers. In addition, EUV lithography can generate a wavelength in the range of 20nm to 50nm by using a synchrotron or by striking a material (either solid or plasma) with high-energy electrons in order to generate photons in this range.

Although the concepts disclosed herein can be used for imaging on substrates such as silicon wafers, it should be understood that the concepts disclosed can be used with any type of lithographic imaging system (for example, for They are used together with their lithography imaging systems for imaging on substrates other than silicon wafers.

The above description is intended to be illustrative, not restrictive. Therefore, it will be obvious to those who are familiar with the technology that they can make modifications as described without departing from the scope of the patent application set out below.

510: Crystal Grain

520: Crystal Boundary

610: Native Surface

612: lens

620: light

710: modified surface

720: Crystalline grain peak

730: Crystalline Grain Boundary Valley

Claims (13)

A method for reducing the adhesion of an object to a modified surface for supporting the object in a lithography process, the method comprising: controlling a light source to deliver light to a A native surface, thereby causing ablation of at least a portion of the native surface to increase the roughness of the native surface, thereby forming the modified surface, wherein the increased roughness reduces the adhesion of the object to the The ability of the modified surface, wherein the control includes: setting an energy density of the light source to generate light with a fluence at the original surface, which is based on the original surface when the light is delivered to the surface An atomic structure results in selective ablation of the primary surface, the selective ablation reduces a surface area used to contact the object. Such as the method of claim 1, wherein the light source is a laser. Such as the method of claim 1, wherein the native surface includes a top surface of a burl. According to the method of claim 1, the primary surface includes crystalline grains separated by grain boundaries, wherein the selective ablation removes the material of the grain boundaries and does not substantially cause the crystals Removal of grains. As in the method of claim 1, the controlling further includes: adjusting one or more of an intensity and/or focus of the light source to set the energy density based on a desired roughness of the modified surface. According to the method of claim 1, the controlling further comprises: delivering light at the separation site on the primary surface to cause ablation of a part of the grain boundaries, and the delivering causes the modified surface to include a separation between them. Roughened area. Such as the method of claim 6, wherein the separation distance is greater than a spot size of the light source. Such as the method of claim 1, wherein a distance between the parts of light delivery may be smaller than the size of a light spot of the light source. The method of claim 1, wherein the light delivery spans a plurality of hilltops, and the plurality of hilltops are located on a top surface of a nodule forming a part of a reticle clamp superior. A non-transitory machine-readable medium storing instructions that when executed by at least one programmable processor cause the at least one programmable processor to perform operations, the operations including: controlling a light source to deliver light To a primary surface, thereby causing at least a part of the primary surface to be cut to increase the roughness of the primary surface, thereby forming a modified surface, which The increased roughness weakens the ability of an object to adhere to the modified surface, wherein the control includes: setting an energy density of the light source to generate light with a flux at the original surface, and the light is Delivery to the surface results in selective ablation of the native surface based on an atomic structure of the native surface, and the selective ablation reduces a surface area for contacting the object. For the non-transitory machine-readable medium of claim 10, the control further includes: adjusting one or more of the intensity and/or focus of the light source to set the energy density based on a desired roughness of the modified surface . For the non-transitory machine-readable medium of claim 10, the control further includes: delivering light at the separation site on the primary surface to cause ablation of a part of the grain boundaries, the delivery causing the modified surface to include a Roughened area of distance. A support structure comprising: a modified surface configured to contact an object, the modified surface being formed of a material including a crystal grain structure, the crystal grain structure including crystal grains and grain boundaries, wherein The modified surface has a roughness based at least on a plurality of crystal grain peaks and a plurality of grain boundary valleys located below the crystal grain peaks.

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